JP2012525070A - PA gain state switching based on waveform linearity - Google Patents

Abstract

  Techniques for optimizing the power consumption of existing low-cost multi-gain state power amplifiers (PAs) to increase talk time of wireless communication devices are described. In an exemplary embodiment, a device such as a baseband processor operates to set a multi-stage PA having at least two gain states for amplifying the transmitted signal to the lowest power consumption gain state. The device calculates the transition power level as a function of the identified maximum power reduction (MPR) value, and switches the PA from the low gain state to the high gain state if the transmit power level is higher than the calculated transition power level.

Description

[35U. S. C. Priority claim under Article 119]
This application is entitled “WAVEFORM VARIABLE PA SWITCHPOINTS IMPLEMENTATION IN UE WITH MULTI GAIN STATE PA FOR LOW COST BATTERY LIFE OPTIMIZATION” filed on April 21, 2009, assigned to the assignee of this application and specifically incorporated herein by reference. Claims priority to US Provisional Patent Application No. 61 / 171,299.

  The present disclosure relates generally to electronics, and more particularly to optimizing transmitter power consumption and thereby optimizing talk time for wireless communication devices.

  Radio frequency (RF) signals generated at a mobile handset are typically amplified, transmitted through a handset antenna, and sent to a base station for delivery to a receiver. The frequency band of operation of the handset is often pre-defined mainly in the frequency range of 450 MHz to 2.6 GHz for various mobile standards such as WCDMA (Wideband Code Division Multiple Access) and CDMA (Code Division Multiple Access). It has been established.

  In general, if the handset is far from the receiving base station, the handset needs to transmit at a high output power level in order to maintain a predetermined signal strength at the base station for sufficient reception. Conversely, the closer the handset is to the base station, the less transmission power will be required. The output power of the handset is adjusted using commands embedded in the RF control signal transmitted from the base station to the handset.

  The handset transmit signal and the RF power amplifier output signal may be measured in terms of adjacent channel leakage power ratio (ACLR) that defines the maximum allowable interference to other frequency channels to minimize interference between signals. It must meet government regulations on spectrum regrowth (also known as linearity).

  Some known mobile devices (handsets) have an RF power amplifier that is always powered by a full battery voltage. RF power amplifiers are generally designed to meet linearity specifications at maximum transmit power levels under such bias conditions (eg, +28 dBm in some WCDMA mobile handsets). Statistically, power amplifiers can transmit at maximum linear output power for only a fraction of the time, with most of the transmission occurring at significantly lower power levels (10-20 dB below maximum power).

  The actual output power level from the power amplifier (and from the headset) is continuous from about -50 dBm to 28 dB. Multi-gain state power amplifiers consume less current with lower power output compared to conventional single path power amplifiers.

  Multi-gain state power amplifiers are typically implemented with two or three power gain states. In a three gain state solution, the three states include high power (HP), medium power (MP), and low power (LP). For a normal WCDMA waveform, the HP gain state is set for the desired maximum output power range from 16 dBm to 28 dBm, the MP gain state is set from 8 dBm to 16 dBm, and the LP gain state is for all power levels below 8 dBm. Is set. In short, multi-gain state power amplifiers are implemented with two, three (or more) power paths, each delivering a predetermined maximum output power at a constant gain. The switching point (in dBm) is a value that defines the transition power level at which the handset switches (jumps) from one PA gain state to one above or below. Currently, the multi-gain state PA does not dynamically change this PA switching point to account for inherent differences in the transmitted waveform, such as linearity differences.

  As mentioned above, spectral regrowth can occur when the PA is forced to operate in the non-linear region, and occurs when driving a PA near its own 1 db compression point. Thus, spectral regrowth shows an increase in out-of-band signal energy at the power amplifier output due to the effects of the nonlinear amplifier. Spectral regrowth is most noticeable in the channel adjacent to the desired transmission channel. In the case of UMTS, the requirements in the power amplifier are determined by the +/− 5 MHz adjacent channel leakage ratio (ACLR) of the desired channel. The voltage gain characteristic of the power amplifier can be characterized as follows.

V ₀ (t) = g ₁ v _i (t) + g ₂ v _i (t) ² + g ₃ v _i (t) ³ +… + g _n v _i (t) ⁿ formula (1)
Where g ₁ v _i (t) is the linear gain of the amplifier and the remaining term (ie g ₂ v _i (t) ² + g ₃ v _i (t) ³ +... + G _n v _i (t ) ^N ) represents a non-linear gain. If the signal carries a modulated third generation partnership project (3GPP) radio frequency (RF), a nonlinear term is generated as a result of distortion between modulations, resulting in an increase in error vector magnitude (EVM). In-band distortion terms that result in out-of-band distortion and ACLR increases.

  Multi-code signals, such as signals in UMTS releases 5, 6, and 7 and signals in certain LTE specifications (eg, 3GPP release 8), exhibit an increase in peak-to-average power that results in greater dynamic signal changes. These increased signal changes require increased amplifier linearity, resulting in increased power consumption. Recent results show that direct transfer of dB to dB (ie, the ratio of signal peak power to average power, also known as peak-to-average ratio (PAR)), has no effect on reducing amplifier power. Showed that. Analysis of amplifier spectral regrowth showed that the third order nonlinear gain term (“cubic gain”) was the main cause of ACLR increase. The total energy in the cubic term depends on the statistical distribution of the input signal.

  With the introduction of High Speed Uplink Packet Access (HSUPA), a new method for estimating amplifier power reduction, called Cubic Metric (CM), was introduced in Release 6. CM is based on the cubic gain term of the amplifier. CM represents the ratio of the third order component in the observed signal to the third order component of the 12.2 kbps speech reference signal. CM adapts to both high speed downlink packet access (HSDPA) uplink signals and HSUPA uplink signals. Statistical analysis showed that power reduction based on CM estimation showed a significantly smaller error distribution when compared to power reduction based on 99.9% PAR. In this case, the error distribution is the difference between the actual power reduction and the estimated power reduction.

  3GPP is a maximum power reduction (MPR) test that verifies that the maximum transmit power of a mobile handset is equal to or greater than the normal maximum transmit power, which is less than the amount referred to herein as “maximum MPR”. Is described. In this case, the maximum MPR is a function of the CM of the transmitted signal.

  The handset must know the value of CM to calculate the selected MPR, if necessary (ie if the handset is operating near maximum power) and immediately use this information to transmit The power is actually set from the maximum power level to the transmit power level backed off by an amount equal to MPR. Even if the receiving base station cannot receive a transmission signal at this low (backed off) transmission power level, the standard allows the handset to transmit at a low power level. Since PA is already in the highest gain state and maximum output power level, it cannot be switched to the next higher gain state or power level.

  Any multi-code signal (characterized by the physical channel being transmitted, whose channelization codes and weights are referred to as β terms) has its own specific CM and PAR. In UMTS, the signal and CM and PAR can change every 2 or 10 msec transmission time interval (TTI). For Release 6 UMTS, it is shown that there are more than 200,000 combinations of physical channel parameters and quantized β terms, each of which is referred to herein as a possible signal. Therefore, the handset needs to look up the CM or PAR (by a method such as a look-up table) and measure or estimate these values within some acceptable error from the signal characteristic parameters. . Nevertheless, it is well known to measure CM or PAR from actual signals.

  Speech waveforms are generally associated with high linearity, which means that any relevant linearity metric (eg, cubic metric, PAR, etc.) is high compared to the data waveform. On the other hand, the data waveform has a wide range of linearity metrics.

  Existing PA implementations distinguish between speech and data waveforms, or waveforms that are more linear and waveforms that are less linear, and do not adjust the switching points to account for their linearity differences. As a result, both the speech waveform and the data waveform are improperly switched based on a predetermined switching point regardless of the arbitrary linearity characteristics of the inherent transmission waveform. Battery resources are wasted when the low gain state is more appropriate at a predetermined transmit power level.

  Many vendors offer competing multi-gain state PA solutions. The handset integrator selects the optimal solution for a given reference design, thereby freeing from the obligation to design its own PA solution. One disadvantage of this is that the PA is not fully optimized to provide optimal power usage. For example, a PA solution configured for mobile device applications with multi-mode, multimedia capabilities is optimized for voice rather than data usage, or optimal for specific phone configurations It can be lower than the power transition level. On the other hand, existing off-the-shelf solutions are already shown solutions that are low cost and easy to integrate, where tradeoffs in efficiency are often acceptable or simply cost-effective options for integrators.

Table 1 below shows example PA characteristics for an example multi-gain state PA designed for use in a WCDMA mobile device. The example multi-gain state is designed to operate over three PA gain states, each associated with a specific maximum power output level and a specific gain value.

  As can be seen from Table 1, operating the multi-gain state PA at the lowest possible gain stage consumes significantly less current. Therefore, any baseband processor that sets the operational state of the PA during telephone operation is generally required by the network operator and / or defined by government imposed signal interference rules and regulations or related standard specifications. In order to optimize power consumption without compromising transmission signal degradation, adjacent channel leakage, etc. required to meet the technical specifications of such products, select the optimal power gain state to set the PA. There must be.

  In certain wireless communication protocols, such as WCDMA, portable devices such as handsets must be able to switch to an appropriate output power level and a specific gain state based on predetermined switching points.

  The baseband processor in the handset generally determines and sets the gain states of the three gain states PA by toggling a 2-bit digital input (eg, IC pins Vmode0 and Vmode1). A device with two gain states PA may require a 1-bit digital input instead.

  In WCDMA, the baseband processor can perform rate selection to control or reduce power leakage to adjacent channels that can be incurred by the handset. Rate selection includes selecting the data rate and coding scheme for the intended signaling or burst as a method for controlling the PA response.

  The baseband processor programs the handset transmitter circuit to set up the necessary transmission configuration to enable uplink transmission. The transmitter configuration can be characterized by one or more channels in code, frequency, or time domain, or combinations thereof, and can include other attributes, such as channel modulation type.

  An uplink transmission configuration for WCDMA may be characterized by two or more code channels using different modulations, spreading factors, channelization codes, and I-branch assignments or Q-branch assignments. For example, multi-channel WCDMA uplink transmissions are (i) dedicated physical control channel (DPCCH), (ii) dedicated physical data channel (DPDCH), (iii) high-speed dedicated to support a single transmission link event. It may include a physical control channel (HS-DPCCH), (iv) an advanced dedicated physical control channel (E-DPCCH), and (v) an advanced dedicated physical data channel (EDPDCH).

  Possible transmission mechanisms in multi-mode devices that can support new and old releases of radio protocols, and multi-mode devices that can support other radio protocols (eg, CDMA1x, CDMA2000, OFDM, etc.) The number of results can be quite large.

  It is known that a given transmitter configuration tends to make the PA more linear or less linear than another transmitter configuration. For this reason, protocols such as WCDMA assume the baseband processor has the worst case peak-to-average power response for a given uplink transmission, and the headset considers MPR as described above. Require this to be considered by requesting to do.

  In terms of signal gain, the actual power gain difference between the low gain state and the next higher gain state is very small. Referring to Table 1, for example, the difference in actual power gain (ie, Pout / Pin) between the low gain state and the medium gain state is only 1 dB.

  Once the required transmitter configuration is set, the waveform characteristics of the uplink transmission signal can vary depending on the type of signal being transmitted.

  The main problem with the multi-gain state PA is the difficulty (in terms of high design cost) of changing the bias and reference voltage that sets the PA to account for nonlinear changes across the dynamic range of transmit power. is there.

  One well-known approach to account for non-linearity changes is generally to use a single gain state PA that is externally driven by various switch mode power supplies (SMPS). The SMPS changes the voltage supplied to the PA more accurately over the desired transmission dynamic range, thereby improving battery-induced current due to the effects of SMPS. SMPS is intentionally avoided because it is a large and expensive part. The use of SMPS also calculates the associated linearity metric for each waveform on-the-fly and programs the SMPS to set any bias, reference, etc. PA settings that adjust the PA to the desired gain state. It is necessary to generate an appropriate signal for.

  It is highly desirable to be able to switch more efficiently between the gain states of the multi-gain state PA in order to take into account the non-linear characteristics of the waveform.

FIG. 1 shows a system level block diagram of a wireless communication device. FIG. 2 shows a low-level block diagram of a logic circuit for switching and calculating between gain states of a multi-gain state power amplifier using MPR according to an exemplary embodiment. FIG. 3 shows an example of switching point values based on MPR values associated with different linear waveforms according to an exemplary embodiment. FIG. 4 shows a flow diagram for switching and calculating between gain states of a multi-gain state power amplifier according to an exemplary embodiment.

Detailed description

  For ease of understanding, the same reference numbers may designate the same elements that are common to the figures, except where additional numbers are appended to distinguish the elements. The images in the drawings are simplified for illustrative purposes and are not necessarily shown to scale.

  The accompanying drawings illustrate exemplary configurations of the present disclosure, and should not be viewed as limiting the scope of the present disclosure, which recognizes other configurations that are equally effective. Accordingly, it was contemplated that features of some configurations could be conveniently incorporated into other configurations without further description.

  The word “exemplary” is used herein to mean “provide an example, instance, or illustration”. Any embodiment described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments.

  The detailed description set forth below in connection with the appended drawings is intended as a description of exemplary embodiments of the invention and is not intended to represent the only embodiments in which the invention may be practiced. The term “typical” as used throughout this description means “provides an example, instance, or illustration” and is not necessarily to be construed as preferred or advantageous over other embodiments. is not. The detailed description includes specific details for the purpose of providing a thorough understanding of the exemplary embodiments of the invention. It will be apparent to those skilled in the art that the exemplary embodiments of the present invention may be practiced without these specific details. In some instances, well-known structures and devices are shown in block diagram form in order to avoid obscuring the novelty of the exemplary embodiments presented herein.

  Those skilled in the art will understand that information and signals may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referred to throughout the above description are by voltage, current, electromagnetic wave, magnetic field or magnetic particle, light field or optical particle, or any combination thereof. Can be represented.

  This disclosure describes techniques for more accurate switching between gain states of a multi-gain state PA that takes into account the actual waveform linearity characteristics of the transmitted signal.

  FIG. 1 shows a system level block diagram of a wireless communication device 100. The wireless communication device 100 may be configured to be able to control the PA gain state according to embodiments described below.

  A wireless communication device (WCD) 100 may be a handset, portable device, user equipment (UE), modem device, or any such similar device.

  WCD 100 includes a baseband processor (BB) 110, a transceiver 120, and an antenna 125. The transceiver 120 comprises a transmitter 130, a receiver 150, an LO generator 170, and a PLL 172 that together provide support for two-way wireless communication over a wireless channel to a remote terminal device or base station.

  In general, WCD 100 may include multiple transmitters 130 and multiple receivers 150 to support simultaneous multi-mode communication and multiple protocols over multiple frequency bands. Each transceiver may have one or more transmit and receive paths and includes only one type of path and no other types of paths.

  WCD 100 selects the desired transmitter configuration required to transmit the waveform (data or voice).

  In the example transmitter configuration, transmitter 130 receives the digital output signal from BB 120. This signal is first fed to a digital-to-analog converter (DAC) (132) and then analog, such as a low-pass filter 134, to remove any image generated by the digital-to-analog conversion. Filtered by a filter The output from low pass filter 134 is then upconverted from baseband level to RF by mixer 138, and the upconverted RF signal is filtered by filter 140. The output from the filter 140 is further amplified by a driver amplifier (DA) 142 and finally supplied to a power amplifier (PA) 144. The output from PA 144 is routed through duplexer / switch 146 and finally transmitted via antenna 125.

  In the example receive path as shown, antenna 125 receives a signal from a base station and provides a received signal. This signal is routed through duplexer / switch 146 and provided to receiver 150. Within receiver 150, the received signal is amplified by LNA 152, filtered by bandpass filter 154, and downconverted from RF to baseband by mixer 156. The downconverted baseband signal is filtered by an analog filter, such as a low pass filter 160, and then amplified by an amplifier 162 to obtain an analog input signal that is input to the BB 110. In an alternative configuration, both the input to BB 110 and the output from BB 110 are either digital signals and / or both analog signals, or some combination of both.

  As shown in FIG. 1, transmitter 130 and receiver 150 implement a direct conversion architecture that frequency converts signals between RF and baseband in one stage. Transmitter 130 and / or receiver 150 may also implement a super-heterodyne architecture that frequency converts signals between RF and baseband in multiple stages.

  A local oscillator (LO) generator 170 generates a transmit LO signal and a receive LO signal and provides them to mixers 138 and 156, respectively. A phase lock loop (PLL) 172 receives control information from the BB 110 and provides control signals to the LO generator 170 to generate transmit and receive LO signals at the appropriate frequencies.

  In general, signal conditioning at transmitter 130 and receiver 150 may be performed by one or more stages such as amplifiers, filters, mixers, and the like. These circuit blocks can be rearranged so as to be different from the configuration shown in FIG. In addition, other circuit blocks not shown in FIG. 1 may also be used to condition the signals at the transmitter and receiver. Some circuit blocks in FIG. 1 may be omitted. Part or all of the transmitter 120 may be implemented in an analog integrated circuit (IC), RF IC (RFIC), mixed signal IC, or the like. For example, the amplifier 132 to the driver amplifier 142 in the transmitter 130 can be mounted on the RFIC, and the power amplifier 144 can be mounted outside the RFIC.

  The BB 110 can perform various functions of the wireless communication device 100, such as digital processing of transmitted and received data. The memory 112 can store data and program codes for the BB 110. The BB 110 may be implemented on one or more application specific integrated circuits (ASICs) and / or other ICs.

  As shown in FIG. 1, the transmitter and receiver can include a plurality of different amplifiers. Each amplifier can be implemented in various ways. Unless preset, the BB 110 is typically set up to control the gain level or gain state and the output power level of each amplifier.

  The BB 110 selects the data rate and coding scheme (eg, based on rate selection) for signal transmission or burst over the radio channel for a given transmitter configuration. The BB 110 will also calculate a maximum power reduction (MPR) based on waveforms generated for a given transmitter configuration in a well-known manner. The MPR is usually defined by the associated wireless communication protocol (eg, 3GPP standard) to control how much the WCD 100 must back off from the maximum transmit power (MTP) or transmit the corresponding waveform. Used to adjust the MTP to establish a modified MTP used in and ensure that the adjacent channel leakage level stays within the specified or targeted range.

  WCD 100 may also calculate MPR based on the cubic metric of the waveform generated for a particular transmitter configuration. The number of transmitter configurations can be quite large and each configuration has a corresponding MPR. During rate selection, among other parameters, the data rate, coding scheme, and transmitter configuration are determined using well-known techniques. As a result, both the waveform and transmitter configuration are known before signal transmission. This information can be used to calculate or determine the MPR and apply that MPR to determine the maximum transmit power level in time for the transmission of the waveform.

  To date, MPR has been used only to determine how much to back off the maximum power level rating of the PA at the high end of the power curve, ie, the power provided in the HP gain state. The MPR is to set the switching point or to control when the PA switches from one gain state to the next as a function of MPR or some other linearity characteristic of the transmitted signal waveform. Not used.

  As explained above, wireless communication protocols such as those based on the 3GPP protocol, for example, require the calculation of MPR. The MPR score or MPR value is divided into groups or “bin” waveforms in MPR increments of 0.5 dB or 1 dB steps depending on the particular 3GPP standard. For example, in 3GPP 25.101 Release 5 (HSDPA), the maximum power backoff is related to the specific waveform linearity characteristics set in different “bin” tables in 1.0 dB increments. Similarly, 25.101 Release 6 (HSUPA) and beyond, the value used to assign the waveform to the “maximum power reduction” value from the bin of maximum power backoff values separated in 0.5 dB increments. Use "cubic metric" to calculate. In addition, 36.101 Release 8 (LTE) defines the MPR using the waveform property via the MPR value table set in the “bin” of 1.0 dB. For the purposes of this disclosure, the terms MPR and maximum power backoff are used interchangeably to refer to any value (or set of values) intended to define a maximum power backoff parameter. It should be understood that

According to an exemplary embodiment, WCD 100 (and especially baseband processor 110) not only adjusts and lowers the maximum allowed transmit power of wireless communication device 100, but also reduces PA from the low power gain state to the next. A predetermined or calculated MPR value is also used to determine a more optimal switching point for switching to a different power gain state level. Since MPR is known as priority, there is no additional resource that is expanded by the BB processor to recalculate. (However, it is contemplated herein to calculate MPR or any other waveform-related characteristic metric, including cubic metric, PAR, any combination of metrics, etc., on-the-fly or using a look-up table. Using them to set or move switching points is an equally applicable alternative to the use of well-known MPR values.)
FIG. 2 shows a low-level block diagram of a logic circuit for switching and calculating between gain states of a multi-gain state power amplifier using MPR, according to an exemplary embodiment.

  Here, a baseband processor 202 (corresponding to BB 110 in FIG. 1) comprising an MPR module 204 coupled to a PA gain controller 206 is shown. Baseband processor 202 is programmably coupled to multi-gain state power amplifier (PA) 210 (corresponding to PA 144 in FIG. 1) via PA gain controller 206. The PA gain controller 206 toggles the PA gain state control state signals (Vmode0, Vmode1) and sets the PA to the desired gain state or a new state (higher or lower) according to the exemplary embodiment described below. PA control signal 218 to be changed to (gain state) is generated.

  The output of PA 210 is coupled to antenna 214 to facilitate transmission of a spatially modulated waveform.

  Baseband processor 202 provides the transmit signal to multi-gain state PA 210 through transmit path 216 (shown in dotted lines and substantially corresponding to the transmit path of FIG. 1).

  In one exemplary embodiment, the MPR module 204 is a well-known method for determining the maximum transmit power level at the high end of signal power transmission, based on the associated communication protocol of the signal, one or more transmit signals. The MPR value is generated. The same value is then provided to the PA gain controller 206. The PA gain controller uses the received MPR value to determine if it is appropriate to shift the switching point by an MPR based value. This is because the waveform characterized by more or less linearity at the current power gain state level and for preset switching points, the transmitter does not need to switch to a higher gain state for many more changes by the receiver. This is to take into account the fact that reception is possible without causing distortion.

  FIG. 3 schematically illustrates an example of switching point values based on MPR values associated with different linear waveforms according to an exemplary embodiment.

  Each PA transition power level corresponds to a different PA switching point value. PA transition power level when MPR = 0 (line 250), PA transition power level when MPR is greater than zero (0) but less than the maximum MPR value (= MAX (MPR)) (line 260) , And three switching point values based on PA transition power level (line 270) when MPR is equal to MAX (MPR). For reference purposes, the base or initial switching point value, xdBM at MPR = 0, is assumed in line 250.

  Each of the three switch value states represents a new point at which the PA gain controller 206 selects when to shift the PA 210 from the low gain state to the high gain state and vice versa. Since the switch point value is based on MPR, i.e. associated with the linearity metric of the transmitted signal, if the transmitted waveform is more linear, to the first threshold that the PA needs to move to a higher gain state. When shifting up and the transmit waveform being less linear, it is possible to shift the switching point to a state where the PA is shifted down to a second threshold that needs to move to a higher gain state. In one scenario, the first and second thresholds are the same value and correspond to the switching point value xdBm. In another scenario, the first and second thresholds are the same, corresponding to the maximum output power level in each gain state.

The new switching point threshold can be expressed numerically as follows:
New switching point threshold (dBm) =
New transmit power level (dBm) =
xdBm-MPR value (dB) Equation (2)
The MPR value is determined using the associated beta factor associated with a given transmit signal waveform. Therefore, equation (2) can be expressed more appropriately as follows.
New switching point threshold (dBm) =
New transmit power level (dBm) =
xdBm-MPR value (βc, βd, βca, βcc, βcd,) (dB) Equation (3)
In addition to using MPR as defined in 3GPP, it is possible to modify the bins or groups of waveforms and group or associate them with different bins than those generally defined by the 3GPP standard, for example .

  In an exemplary alternative embodiment, the MPR values are binned based on a linearity factor such as a cubic metric calculation. In the case of a speech waveform, for example, the speech waveform has a cubic metric result that is 1 dB lower than the highest arbitrary linearity data waveform that can be transmitted. However, the 3GPP standard “binds” Rel99 WCDMA voice with such data waveforms and treats both as belonging to bin MPR = 0.

  To account for the linearity MPR value imbalance, a dedicated “bin” can be generated and assigned the value MPR = −1. The speech waveform will be automatically assigned to the minus 1 (-1) MPR value and bin MPR = -1 used to calculate a new switching point for Equations 2 and 3 above. The remaining implemented bins can be implemented identically to 3GPP MPR bins or allow the baseband processor to reduce power consumption by controlling when the PA should be switched between states Can be modified to take into account other factors.

  An example of a 25.101 Release 6 (HSUPA) implementation implemented using Release 99 voice bins can include all of the following bins: MPR = -1 dB, MPR = 0 dB, MPR = 0.5 dB, MPR = 1.0 dB, MPR = 1.5 dB, MPR = 2.0 dB, and MPR = 2.5 dB.

  Each of the above waveform “bins” will have its own switching point power level in the example of a three gain state PA for going from a low PA gain state to a high PA gain state and vice versa.

  This allows each “bin” of the waveform to be switched to their maximum linearity function, resulting in a design that achieves good power consumption at the desired power level for more waveforms The linearity function of the selected PA gain state can be optimized.

  Thus, the PA gain controller 206 will only change the multi-gain state PA when the MPR value of the transmit waveform requires the multi-gain state PA to switch to the next gain state to support the transmit waveform linearity requirement. Do not switch to a higher gain state. Or conversely, if the waveform MPR value is low enough that the waveform can be transmitted linearly by a multi-gain state PA operating in a low-gain state, the PA gain controller may PA will be switched to the low gain state.

  One skilled in the art will appreciate that “binning” can follow MPR or any other similar linearity metric.

  An example of binning based on the current 3GPP standard is shown below.

  25.101 Release 5 (HSDPA) defines MPR using waveform properties via table assignment of waveforms to bins in 1.0 dB “bin” increments.

  25.101 Release 6 (HSUPA) and beyond uses a “cubic metric” that calculates the MPR and assigns the waveform in 0.5 dB “bin” increments.

  36.101 Release 8 (LTE) defines MPR with waveform properties via a table in 1.0 dB “bin” increments.

  FIG. 4 is a flow diagram for switching and calculating between gain states of a multi-gain state power amplifier according to an exemplary embodiment.

  In the exemplary embodiment of FIG. 4, a transmit power level for transmitting a signal is first determined (step 310). At step 320, the waveform linearity characteristics associated with the signal are identified. Next, in step 330, a waveform bin associated with the identified waveform linearity characteristic is identified from the plurality of waveform bins. Each waveform bin is associated with an MPR value. Accordingly, at step 340, the MPR value associated with the identified waveform bin is identified. In a next step 350, at least one new transition power level (new switching point) between the two gain states is calculated as a function of the identified MPR value.

  This function obeys the following rules:

  Let the transmission power level for MPR = 0 dB be waveform = xdBm.

  The specific transition power level for each waveform bin is a function of the MPR value according to the following equation:

Transition power level (dBm) = xdBm-MPR (dB)
After the transition power level is calculated, in step 306, the transition power level and the transmission power level are compared.

  The determination of whether the PA switches to a different gain state is a function of the calculated transition power level, transmit power level, and current PA gain state.

  If the PA is in the low gain state and the transmit power level is greater than the transition power level, in step 370 the PA switches to the high gain state.

  If the PA is in the low gain state and the transmit power level is lower than the transition power level, in step 308, the PA remains in the low gain state.

  If the PA is in the high gain state and the transmit power level is greater than the transition power level, the PA remains in the high gain state.

  If the PA is in the high gain state and the transmit power level is lower than the transition power level, the PA switches to the low gain state.

  By dynamically calculating the transmit power level as a function of MPR value, the PA stays in the low gain state longer and switches to the low gain state more quickly. If the MPR value for a particular waveform bin is not used in the equation, the PA generally switches to the high gain state faster or stays longer in the high gain state. Thus, by introducing the MPR value into the formula for calculating the transition power level, the PA gain state switching is optimized, thereby reducing the current used by the PA and increasing the battery duration and UE talk time. .

  In a further step, a waveform dedicated to a particular type of signal, such as speech, which has a substantially better waveform linearity characteristic compared to the waveform linearity characteristics of other types of signals such as data, for example. A bin is assigned. The waveform bin for the audio signal has an MPR value = −1 dB.

  One skilled in the art will recognize that this method includes any transmitter or receiver waveform linearity metric other than MPR, cubic metric, or peak-to-average so that data packet based protocols can be deployed. You will understand that it can be expanded.

  Those skilled in the art further recognize that the various exemplary logic blocks, modules, circuits, and algorithm steps described in connection with the embodiments disclosed herein are electronic hardware, computer software, or It will be understood that it can be implemented as a combination of To clearly illustrate this interchangeability between hardware and software, various illustrative components, blocks, modules, circuits, and steps have been generally described above in terms of their functionality. Whether such a function is realized as hardware or software depends on design constraints imposed on the entire system and a specific application. Those skilled in the art can implement the above described functions in various ways for each particular application, but such implementation decisions are interpreted as deviating from the scope of the exemplary embodiments of the present invention. Must not be done.

  Various exemplary logic blocks, modules, and circuits described in connection with the embodiments disclosed herein can be general purpose processors, digital signal processors (DSPs), application specific integrated circuits (ASICs), field Programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or those designed to perform the functions described herein It can be implemented or implemented using any combination. A microprocessor can be used as the general-purpose processor, but any conventional processor, controller, microcontroller, or state machine can be used instead. The processor may also be a combination of computer devices such as a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors connected to a DSP core, or any other such configuration. Can be implemented.

  The algorithm or method steps described in connection with the embodiments disclosed herein may be implemented directly by hardware, by software modules executed by a processor, or by a combination of the two. Software modules include random access memory (RAM), flash memory, read only memory (ROM), electronic programmable ROM (EPROM), electronic erasable programmable ROM (EEPROM), registers, hard disk, removable It can be stored on a disk, CD-ROM, or any other form of storage medium known in the art. An exemplary storage medium is coupled to the processor such that the processor can read information from, and write information to, the processor. In the alternative, the storage medium may be integral to the processor. The processor and the storage medium can reside in an ASIC. The ASIC can exist in the user terminal. In the alternative, the processor and the storage medium may reside as discrete components in a user terminal.

  In one or more exemplary embodiments, the functions described may be implemented by hardware, software, firmware, or any combination thereof. If implemented in software, the functions may be transmitted or stored as one or more instructions or code on a computer-readable medium. Computer-readable media includes both communication media and computer storage media including any medium that facilitates transfer of a computer program from one place to another. A storage media may be any available media that can be accessed by a computer. By way of example, and not limitation, such computer-readable media can be RAM, ROM, EEPROM, CD-ROM or other optical disk storage media, magnetic disk storage media or other magnetic storage devices, or instructions or data structures. Any other medium that can carry or store the desired program code in a form and that can be accessed by a computer can be provided. Also, any connection is referred to as a computer readable medium as appropriate. For example, the software can be from a website, server, or other remote source, coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless such as infrared, radio, and microwave When transmitted using technology, coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the media definition. As used herein, a disk and a disc are a compact disc (CD), a laser disc (disc), an optical disc (disc), a digital versatile disc (disc). (DVD), floppy disk, and Blu-ray disk. A disk generally reproduces data magnetically, and a disk optically reproduces the disk using a laser. Combinations of the above should also be included within the scope of computer-readable media.

  The previous description of the disclosed exemplary embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these exemplary embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Can be done. Accordingly, the present invention is not intended to be limited to the embodiments shown herein, but is intended to be accorded the widest scope consistent with the principles and novel features described herein. ing.

Claims (26)

A device for controlling a multiple gain state power amplifier (PA) having at least two gain states for amplifying a transmitted signal comprising:
An MPR module for calculating a transition power level between a low gain state and a high gain state as a function of a maximum power reduction (MPR) value associated with the transmitted signal;
A PA gain controller for switching the PA from a low gain state to a high gain state when a transmit power level is higher than the transition power level.   The device of claim 1, wherein the MPR module comprises a metric for identifying the MPR value.   The device of claim 2, wherein the PA gain controller compares the transmit power level and the transition power level to determine an optimal gain state to minimize current consumption of the PA. An integrated circuit (IC) for controlling a multi-gain state power amplifier (PA) having at least two gain states for amplifying a transmitted signal,
A module for calculating a transition power level between the PA gain states as a function of an MPR value associated with the transmitted signal;
An IC comprising: a PA gain controller for switching the PA from a low gain state to a high gain state when a transmission power level is higher than the transition power level;   The IC of claim 4, wherein the MPR module comprises a metric for identifying the MPR value.   6. The IC of claim 5, wherein the PA gain controller compares the transmit power level and the transition power level to determine an optimal gain state to minimize current consumption of the PA. A wireless communication device (WCD) having a multiple gain state PA having at least two gain states for amplifying a transmission signal,
An MPR module for calculating a transition power level between the PA gain states as a function of an MPR value associated with the transmitted signal;
A WCD comprising a PA gain controller for switching the PA from a low gain state to a high gain state when the transmission power is higher than the transition power level.   The WCD of claim 7, wherein the MPR module comprises a metric for identifying the MPR value.   9. The WCD of claim 8, wherein the PA gain controller compares the transmit power level and the transition power level to determine an optimal gain state to minimize current consumption of the PA. A device for controlling a multi-gain state PA having at least two gain states for amplifying a transmission signal,
Means for calculating the transition power level as a function of the identified MPR value;
Means for switching the PA from a low gain state to a high gain state when a transmit power level is higher than the calculated transition power level.   The device of claim 10, further comprising means for switching from a high gain state to a low gain state when a transmit power level is lower than the calculated transition power level.   The device of claim 10, further comprising means for identifying the MPR value associated with the identified waveform bin.   The device of claim 12, further comprising means for identifying the waveform bin associated with the identified waveform linearity characteristic from a plurality of MPR bins.   The device of claim 13, further comprising means for identifying the waveform linearity characteristic associated with the transmitted signal.   The device of claim 14, further comprising means for determining the transmission power level for transmitting the transmission signal.   16. The device of claim 15, further comprising means for assigning MPR values to waveform bins according to the type of transmission signal.   The device of claim 16, wherein the MPR value = −1 dB when the transmission signal is voice. A method for controlling a multi-gain state PA having at least two gain states for amplifying a transmission signal, comprising:
Calculating a transition power level as a function of the identified MPR value;
Switching the PA from a low gain state to a high gain state if a transmit power level is higher than the calculated transition power level.   The method of claim 18, further comprising switching from a high gain state to a low gain state if a transmit power level is lower than the calculated transition power level.   The method of claim 18, further comprising identifying the MPR value associated with the identified waveform bin.   21. The method of claim 20, further comprising identifying the waveform bin associated with an identified waveform linearity characteristic from a plurality of waveform bins.   The method of claim 21, further comprising identifying the waveform linearity characteristic associated with the transmitted signal.   23. The method of claim 22, further comprising determining the transmission power level for transmitting the transmission signal.   23. The method of claim 22, further comprising assigning MPR values to waveform bins according to the type of transmission signal.   The method according to claim 24, wherein the MPR value = -1 dB when the transmission signal is voice. A computer program product for use with a processor device for controlling a multi-stage PA having at least two gain states for amplifying a transmitted signal, the processor device comprising:
Let the transition power level be calculated as a function of the identified MPR value;
A computer program product comprising instructions for switching the PA from a low gain state to a high gain state when a transmit power level is higher than the calculated transition power level.

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